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Re: [RFC] How to add vector math functions to Glibc
- From: "Carlos O'Donell" <carlos at redhat dot com>
- To: "H.J. Lu" <hjl dot tools at gmail dot com>
- Cc: Andrew Senkevich <andrew dot n dot senkevich at gmail dot com>, "Joseph S. Myers" <joseph at codesourcery dot com>, libc-alpha <libc-alpha at sourceware dot org>
- Date: Thu, 25 Sep 2014 15:55:41 -0400
- Subject: Re: [RFC] How to add vector math functions to Glibc
- Authentication-results: sourceware.org; auth=none
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On 09/25/2014 03:37 PM, H.J. Lu wrote:
> On Thu, Sep 25, 2014 at 12:27 PM, Carlos O'Donell <carlos@redhat.com> wrote:
>> On 09/25/2014 11:40 AM, H.J. Lu wrote:
>>> On Thu, Sep 25, 2014 at 8:17 AM, Andrew Senkevich
>>> <andrew.n.senkevich@gmail.com> wrote:
>>>>> If consensus ends up being to have such a library (libmvec or libmvect?),
>>>>> then the installation rules for libm.so as a linker script should go in
>>>>> math/Makefile, not the toplevel Makerules. (I don't know what if any
>>>>> changes might be needed to allow subdirectories to provide libraries as
>>>>> linker scripts.)
>>>>
>>>> There were three options about the place where to add vectorized math functions:
>>>>
>>>> 1. GLIBC (libm)
>>>> 2. GLIBC (additional library)
>>>> 3. GCC
>>>>
>>>> In GLIBC cases build of vectorized functions can be conditional, no
>>>> additional -lmvec required because of libm.so installed as linked
>>>> script in case of vectorized functions available, so it seems not very
>>>> important whether functions located in additional library or in libm.
>>>>
>>>
>>> I don't think they should be in libm since most of applications
>>> won't use those vector functions, which increase libm size
>>> unnecessarily. A separate library is better.
>>
>> I agree. A distinct libmvec.so is best.
>>
>> I see the consensus that #2 is the way forward.
>
> Since this vector library targets GCC, there are
> pros to put it in GCC.
Sorry, I don't understand this part, and perhaps that's why I didn't
understand question 7 in the previous post.
What does it mean for the vector library to target GCC?
Cheers,
Carlos.